Image sensor, multi-chip module type image sensor and contact image sensor

Abstract

The invention is to suppress a loss in image quality resulting from a sensitivity difference among different colors and to suppress an increase in a chip area. The invention provides for example an image sensor including three light detecting element rows respectively having R, G and B color filters on light detecting apertures, in which the light detecting element in the G light detecting element row has a light detecting area larger than that of the light detecting element in other B and R light detecting element rows and centers of gravity of light detecting parts of the light detecting elements in the respective light detecting element rows are arranged with a constant pitch (pitch Q) among the light detecting element rows and in which the G light detecting element row with a larger light detecting area in the light detecting element is not positioned as an end row among the R, G and B light detecting element rows but as a central light detecting element row.

1. An image sensor comprising at least three light detecting element rows each having plural light detecting elements and a color filter provided on each light detecting element, and a peripheral circuit unit for controlling and outputting a photo signal generated by the light detecting elements of the at least three light detecting element rows, in which the light detecting element in one of the light detecting element rows has a light detecting area smaller than that of the light detecting element of other light detecting element rows, and the light detecting element rows are arranged such that centers of gravity of light detecting parts of the light detecting elements of the respective light detecting element rows are arranged at a constant pitch:
 wherein the light detecting element row with a smaller light detecting area in the light detecting element is positioned, among the at least three light detecting element rows, in an end row at a side of the peripheral circuit unit. 
 
     
     
       2. An image sensor according to  claim 1 , where a pitch of the at least three light detecting element rows along a direction of arrangement thereof is equal to or an integral multiple of a pitch of the light detecting elements along a direction of array thereof in the at least three light detecting element rows. 
     
     
       3. A multi-chip module type image sensor comprising a plurality of image sensors according to  claim 1 , positioned in such an array that end portions thereof are mutually adjacent. 
     
     
       4. A contact image sensor comprising a multi-chip module type image sensor according to  claim 3 , a light source for irradiating an object of image reading with a light, and an optical system for guiding a light from the object of image reading to the multi-chip module type image sensor. 
     
     
       5. A contact image sensor according to  claim 4 , wherein the light source is an LED having light emission characteristics corresponding to spectral characteristics of the color filter. 
     
     
       6. An image reading apparatus comprising a contact image sensor according to  claim 4 , and a roller for conveying an original, constituting the object of image reading, to the contact image sensor. 
     
     
       7. An image sensor according to  claim 1 , wherein light detecting elements in a same row have color filters of a same color, and color filters of different rows are of different colors row by row.